test0r 490e688cc1 v0.5.0: add hub — fleet-wide MCP broker
One lmcp server on a central host (typically hertz) that proxies
remote_* tools to every backend in a registry, with a clean SSH
fallback for hosts whose lmcp is temporarily down or not installed.

Tools: remote_list_hosts, remote_{shell,read_file,write_file,edit_file,
list_dir,search_files}. Each takes a `host` argument naming the target
in /opt/herding/etc/hub-backends.conf (or $LMCP_HUB_BACKENDS).

Lazy 30s health cache; `remote_list_hosts force=true` bypasses it.
Bearer auth on inbound (standard lmcp opts.conf / LMCP_TOKEN machinery);
backend Bearer tokens kept in the registry and forwarded per-call.

SSH fallback uses `ssh host 'bash -s' < local_script` — stdin-piped
script body is the canonical shell-escape-free technique. Covers
shell/read_file/write_file/list_dir/search_files. edit_file is lmcp-only
because the literal-match + uniqueness check is nontrivial to replicate
safely in shell.

Ships an example systemd unit and a commented backends.conf template
in examples/. No migration required for existing lmcp deployments —
hub.lua is additive alongside the existing server.lua.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-19 12:29:13 +00:00
2026-04-14 19:58:40 +00:00
2026-04-14 19:58:40 +00:00
2026-04-14 19:58:40 +00:00

lmcp — Lua MCP server

Lightweight Model Context Protocol (MCP) server in pure Lua.

Runtime dependencies

  • Lua 5.1+
  • luasocket — needed for the TCP listener. Packaged as lua-socket on Arch/ALARM, lua-socket on Debian.

Files

File Role
lmcp.lua library: protocol handling, tool registration
server.lua HTTP server loop
json.lua vendored JSON encoder/decoder
example_server.lua sample server with a couple of tools

Install

Packaged as lmcp in the marfrit overlay repo:

# Arch / ALARM
sudo pacman -S lmcp

# Debian
sudo apt install lmcp

Files land under /usr/share/lua/5.4/ (Lua LUA_PATH). The example server installs as /usr/bin/lmcp-example.

S
Description
Lightweight MCP server in pure Lua. 2MB RSS. Zero deps beyond luasocket.
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